Chronic assessment of ALGEL® for endovascular embolization of an arteriovenous malformation model in swine

We sought to assess the stability of ALGEL (Neural Intervention Technologies, Ann Arbor, MI) as an embolic agent in an animal model of a cerebral arteriovenous malformation (AVM). Swine cerebral AVM models were used to test the mechanical stability and biocompatibility of ALGEL as an occlusive agent in a pre-clinical study for up to 6 month survival. The swine cerebral AVM model included a carotid-jugular anastomosis to increase flow to the rete mirabile (RM), thereby simulating the pressure gradient and shunted blood flow of an AVM. ALGEL and the reactive component, calcium chloride, were injected through double-lumen microcatheters to form an RM occlusion in chronic swine models. ALGEL injection blocked blood flow to the inferior portion of the RM, but left flow open to the superior portion of the RM and the circle of Willis. One- and six-month survival results showed that the ALGEL remained a stable occlusive material. Histology results showed a minor bioactive response and encapsulation of ALGEL, thereby increasing the stability and effective occlusion of the embolization material. ALGEL appears to initiate a bioactive response to maintain a stable and long-term endovascular occlusion.